Colouring anodically oxidised aluminium - after electrochemical colouring, by immersion in silicon- or phosphorus heteropolyacids of molybdenum or tungsten

Combination-colouring of Al or Al alloy articles, following anodic oxidn. and electrolytic colouring in an acid soln. of a metal salt with AC 1-50v for 0.1-15min., is effected by immersing the article in an aq. soln. of a heteropolyacid of Si or P with Mo or W, whereby, without supplying current, an...

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Bibliographic Details
Main Authors KELLER, JENS, GEDDE, OVE CHRISTOPHER, GRAALUM PER SARPSBORG (NORWEGEN), KELLER, EBERHARD
Format Patent
LanguageEnglish
German
Published 03.07.1975
Edition2
Subjects
APPARATUS THEREFOR
CHEMISTRY
ELECTROFORMING
ELECTROLYTIC OR ELECTROPHORETIC PROCESSES
METALLURGY
PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS
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Summary:Combination-colouring of Al or Al alloy articles, following anodic oxidn. and electrolytic colouring in an acid soln. of a metal salt with AC 1-50v for 0.1-15min., is effected by immersing the article in an aq. soln. of a heteropolyacid of Si or P with Mo or W, whereby, without supplying current, an electrochemical reaction sets in with the previously electrolytically incorporated metal ions which are more electronegative than Cu in the electromotive series. Method is used for forming decorative and/or wear-and weather-resistant coatings for internal and external use. Durable gray shades are obtd. Heteropolyacid can be prepd. in situ by reacting Na molybdate or tungstate with Na silicate or phosphate and HCl in an aq. soln.
Bibliography:Application Number: DE19732364405